Synchronizing device.



PATENTED APR. 12, 1904.

No. 756,937. N. E. CHURCH.

SYNCHRONIZING DEVICE. APPLICATION FILED SEPT. 27,1902. .NO MIODEL.

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UNITED STATES Patented April 12, 1904.

PATENT OFFICE.

NATHAN E. CHURCH, OF SCHENECTADY, NEW YORK, ASSIGNOE TO GENERAL ELECTRICCOMPANY, A CORPORATION OF NEW YORK.

S-QYNCHRONIZING DEVICE.

SPECIFICATION forming part of Letters Patent No. 756,937, ted April 12,1904-. Application filed September 27, 1902. Serial No. 125,026. (Nomodel.)

To all whom it may concern.-

Be it known that I, NATHAN E. CHURcH, a

citizen of the United States, residing at Schenectady, in the county ofSchenectady, State of New York, have invented certain new and usefulImprovements in Synchronizing Devices, of which the following is aspecification.

This invention relates to alternating-current dynamo-electric machines;and its object is to provide a device for coupling in parallel two suchmachines. ling may be safely effected, the two machines must have thesame frequency and terminal voltage and must coincide in phase.Ordinarily the coupling is effected by hand, the attendant watching somekind of indicator un til it shows that the two machines are nearly instep and then closing a hand-switch to connect the additional machinewith the line. This requires considerable skill, and .one purpose of myinvention is to enable the coupling to be done safely by a lessexperienced person.

I provide each machine with a speed-indicator and group all thespeed-indicators together for facility of observation. I also provideeach additional machine with an automatic circuit-closer, which willoperate only when that machine is in phase with the one already in'circuit;

In the accompanying drawings, Figure 1 is a diagram illustrating myinvention applied to two alternating-current generators, and Fig. 2shows a modification.

The three-phase generator 1 is connectedwith the mains 2 by switches 3and is supposed tobe running at full speed. The additional triphasegenerator 4 is supposed to be coming up to speed; but two of itsconnections withthe mains are open, so that the mains receive no currentfrom the generator 4. Each machine drives a speed-indicator, preferablyof the electric type and comprising a solenoid 5 5, whose core carries apawl 6 6, engaging with a ratchet-wheel 7 7 on whose shaft is an index 88. In circuit with the solenoid is a battery 9 9 and also acircuitcloser, actuated at a predetermined point or In orderthat thecouppoints in the rotation of the generator. The circuitcloser maycomprise a stationary spring-contact 1O 10, insulated from the frame ofthe machine, and a moving contact 11 11, mounted on a rotating part ofthe machine. The terminals of the solenoid-circuit are connected,respectively,with the insulated springcontact and the frame of themachine, so that the circuit is'closed once in each revolution. Theindex will thus be moved along step by step at a speed correspondingwith that of the generator with whichitis connected. By placing the tworatchet-wheels and their attached indices on a common axis the relativespeeds of the two generators can be readily compared. When the speedsare the same, the two indices will maintain the same angular distanceapart as they revolve.

In order to insure a coincidence of phase at the instant the twomachines are coupled, I provide an electromagnetic circuit-closer forthe leads 12 from the generator 4 and arrange a local circuit toenergize said circuit-closer at the proper moment. The preferredarrangement is shown in Fig. 1, where the leads 12 each include adouble-pole switch 13, the two movable contacts of said switches beingcarried on a cross-bar 14:, which can be moved to open the switches by atoggle-link l5 and handle 16. The switches are locked open by aspring-latch 17, which can be tripped by an electromagnet 18, allowing aspring 19 to close the switches. The terminals of the electromagnet areconnected with two springcontacts 20 20', located symmetrically withreference to the rotating parts of'the machines carrying the contacts 1111. Between one of the spring-contacts 20 20 and the electromagnet 18 isa hand-switch 21. The

frames of the machine are connected by a conthrough the electromagnet 18and the switch 13 will close and connect the generator 4cwith the mains.

In Fig. 2 the pawl-actuating armatures 2 1 of the two electromagnets 25which operate the speed-indicators are arranged to close the circuit ofthe battery 23' at the two posts 26. When the two machines attain thesame speed,

the hand-switch 21 is closed, and the instant both magnets operatesimultaneously, which will be only when the two machines are in phase,the electromagnetic swltch Wlll operate.

hat I claim as new, and desire to secure by Letters Patent of the UnitedStates, is

1. The combination with two alternatingcurrent machines, of means forindicating to the attendant when the two machines are running atapproximately the same speed, means for automatically coupling saidmachines in parallel whenever they coincide in phase, and amanually-operated device whereby the attendant can cause said couplingmeans to operate or not, at will.

2. The combination with two alternatingcurrent machines, of anelectromagnetic switch for connecting one of said machines to the line,circuit-closers controlled respectively by the two machines forenergizing said switch when the machines are in phase, and amanuallyoperated device for permitting or preventing the operation ofsaid circuit-closers, at will.

3. The combination with two alternatingcurrent machines, of anelectromagnetic switch for connecting one of said machines, saidcircuit-closers being controlled by the two machines respectively, andbeing closed there by when the machines are at the same point of theirrotation, and a manually-operated device controlling the circuit of saidcircuitclosers.

4c- The combination with two alternating curren t machines,of anelectromagnetic switch for connecting one of said machines to theline, ahand-switch in circuit with the electromagnet, and two circuit-closersin series therewith, each controlled by one of said machines. 5. Thecombination with two alternatingeurrent machines, of a speed-indicatorfor each machine, an electromagnetic switch for automatically connectingone of said machines to line when the two machines are in phase, and

ahand-switch controlling said electromagnetic switch.

6. The combination with two alternatingcurrent machines, of aspeed-indicator for each machine, an electromagnetic switch forconnecting one of said machines to the line, two circuit-closerscontrolled respectively by said machine for energizing said switch whenthe machines are in phase, and a hand-switch in series with theelectromagnetic switch.

1n witness whereof I have hereunto set my hand this 25th day oi?September, .1902.

NATHAN E. CHURCH.

Witnesses:

(at. C. HoLLIsTna, HELEN Onronn.

